Hitherto, the most common bucket tooth used for construction equipment or the like is of a type in which the bucket tooth is fit in an adapter fixedly provided on a bucket side and is fastened by a pin or the like. A bucket tooth of a type which is directly fastened to a bucket by using a bolt is also known.
FIGS. 23(a1) and 23(a2) through FIGS. 23(d1) and 23(d2) show examples of the bucket tooth of the latter type. In each of bucket teeth 50A, 50B, 50C, and 50D, the tip side opposite to a base portion having a plurality of bolt holes 51 is formed with a step, or the base portion is formed in a forked shape. The inner portion of the step or the inner space of the forked portion is placed in contact with the tip of a bucket lip (not shown) and the bucket tooth is fixed to the bucket lip by being bolted.
Another example of the bucket tooth of the bolting type is, as shown in FIGS. 24(a) and 24(b), a bucket tooth 60 of a shape having edges 61 at both one end and the other end and two bolt holes 62, 62 in the center. The bucket tooth 60 can be used twice in such a manner that when the edge 61 at one end is worn and becomes short to the limit, the bucket tooth 60 is turned and the edge 61 at the other end is used.
In the conventional bucket teeth shown in FIGS. 23(a1) and 23(a2) through 23(d1) and 23(d2), however, when the tip of each of the tooth becomes useless by wear, the bucket teeth 50A to 50D have to be replaced by new bucket teeth. Consequently, there is a problem such that the life is relatively short due to the wear, and since the weight of the worn portion with respect to the weight of the whole tooth is small, the yield is low.
On the contrary, in the conventional bucket tooth shown in FIGS. 24(a) and 24(b), even when one of the edges 61 is worn out, the tooth is turned and the other edge 61 can be used. Consequently, it has advantages such that the life is relatively longer in spite of the wear and the yield is higher as compared with the bucket teeth shown in FIGS. 23(a1) and 23(a2) through FIGS. 23(d1) and 23(d2). On the other hand, the bucket tooth has a problem which is common to bucket teeth of the bolting type, such that a fastening bolt is easily loosened due to vibration, shock, and the like applied to the bucket tooth during operation.
The present invention is achieved in order to solve such problems. An object of the present invention is to provide a bucket tooth to be attached by being fastened by a bolt which is prevented from being loosened during operation, and to provide a method of manufacturing the bucket tooth, which can prevent a bolt from being loosened.